The present invention relates to parenteral nutrition and dietary supplements. More particularly, a new synthetic triglyceride family has been developed which provides numerous nutritional benefits and ease of breakdown when used either as a dietary supplement or for total parenteral nutrition. This new structured lipid or synthetic triglyceride has at least one short-chain (2-5 carbon backbone) fatty acid attached to a glycerol backbone.
Structured lipids have recently become a fertile testing ground in the field of parenteral nutrition. Although the ability to form structured lipids through procedures such as transesterification has been known for many years, only recently has an understanding of how the particular fats work in the body when released from a triglycerol backbone been sufficiently developed so as to lead to further exploration of structured lipids for nutritional uses. For example, the nutritional advantages of .omega.3 fatty acids, primarily in the form of fish oil, are now well documented. In like manner, the advantages of medium chain triglycerides (C.sub.8 -C.sub.12) for parenteral nutrition, particularly with hypercatabolic patients, are now being explored. (See, e.g., U.S. Pat. No. 4,528,697.) However, not all structured lipids work alike, nor has it been possible to manufacture structured lipids with particular fatty acids on specific locations of the glycercol backbone until recently.
Although medium-chain fatty acids and long-chain fatty acids have been tested for the nutritional benefits for a long time, only recently has any thought been given to benefits of short-chain fatty acids (2-5 carbon backbone). These short-chain fatty acids are made in the colon from complex carbohydrates and fibrous polysaccarides by bacterial fermentation. These complex carbohydrates, such as pectin and glucans, when broken down to the short-chain fatty acids by the colonic flora, are the preferred fuels for the large and small intestinal cells, e.g., the intestinal mucosa. It has been suggested that short-chain fatty acids could provide nutrition for critically ill patients who cannot obtain sufficient fiber in the diet. This is particularly important since lack of enteric feeding of critically ill patients can lead to translocation of bacteria and endotoxin from the intestinal lumen into vascular system because of thinned intestinal mucosa. This problem is not ameliorated by use of parenteral nutrition since the intestinal cells are often deprived of their necessary nutrition.
However, the simple addition of short-chain fatty acids to parenteral nutrition does not appear to solve these problems. Short-chain fatty acids, when given as fatty acids, are potentially toxic. Moreover, since the short-chain fatty acids are much lower in calories than long-chain fatty acids, either a larger volume of the total parenteral nutrition diet must be used or the calorie content is decreased. Neither of these alternatives are good solutions for treating critically ill patients. In contrast, the synthetic triglyceride proposed herein can provide not only the short-chain fatty acids but also essential .omega.6 long-chain fatty acids as well as long-chain .omega.3 fatty acids.
Accordingly, an object of the invention is to provide a method of delivering short-chain fatty acids to the intestines as part of a total parenteral nutrition diet.
A further object of the invention is to provide a structured lipid containing short-chain fatty acids and medium or long-chain fatty acids.
Another object of the invention is to provide a structured lipid which, when fed enterally, enters the body through the portal system, partially bypassing the lymphatic system, while providing sufficient calories and delivery of the short-chain fatty acids to the intestinal mucosa.
These and other objects and features of the invention will be apparent from the following description and claims.